1. Field
Apparatuses and methods consistent with embodiments relate to an ultrasonic diagnostic apparatus to create a two or three-dimensional image of an internal shape of a target and a control method thereof.
2. Description of the Related Art
An ultrasonic diagnostic apparatus transmits ultrasound to a target to be tested and receives the ultrasound signal reflected from the target. The ultrasonic diagnostic apparatus converts the received ultrasound signal into an electrical image signal to display an internal state of the target. The ultrasound signal is transmitted and received through a probe. The probe includes a transducer to transduce an electrical signal into a transmitting ultrasound signal, and to transduce the ultrasound signal reflected from the target into an electrical image signal. A plurality of transducers arranged in various forms may be used to improve resolution.
Referring to FIG. 1, which shows an example of a probe including a plurality of transducers 10, ultrasound signals transmitted from the respective transducers 10 are set to be simultaneously focused upon a focus point located at a depth d. The distance between a center transducer Tc and the focus point is the shortest, and the distance between an end transducer Tn and the focus point is the longest. A related art ultrasonic diagnostic apparatus includes a transmission beamformer to generate a plurality of transmission signals in view of differences in the distances between the focus point and the respective transducers 10. The transmission beamformer generates a plurality of electrical transmission signals, i.e., transmission beams, based on a delay profile which takes into account the differences in the distances between the respective transducers and the focus point. The transmission beams are transmitted to the respective transducers 10. The transducers 10 transduce the transmission beams into ultrasound signals, which are transmitted to the focus point.
The times needed for the ultrasound signals reflected from the focus point to reach the respective transducers 10 are different. An ultrasound reflection signal directed to the center transducer Tc travels a distance r. On the other hand, an ultrasound signal reaching a transducer Tx distant from the center transducer Tc by a distance x has a time delay corresponding to a difference Δr in the distance between the transducers Tx and Tc and the focus point. The beamformer compensates for the delay in receiving the signals at the respective transducers based on the position of the center transducer Tc.